Leakage control tube mounting for double tube plate heat exchangers



Nov. 24, 1953 N. WEBER LEAKAGE CONTROL TUBE MOUNTING FOR DOUBLE TUBEPLATE HEAT EXCHANGERS Filed Oct. 22. 1949 INVENTOR NICHOLAS WEBERATTORNEY Patented Nov. 24, 1953 LEAKAGE CONTROL TUBE MOUNTING FOR DOUBLETUBE PLATE HEAT EXCHANGERS Nicholas Weber, Teaneck, N. J1, assignortdCondenser Service &- Engineri'ng 011., Inc, Hoboken, N. J., acorporation of New Jersey Application October- 22, 1949, Serial No.122,987

1 Claim.

This invention relates to heat exchangers or surface coolers,particularly of the type for cooling air of motors on board ships andthe like, where impure or salt Water is utilized as a cooling medium forcirculation through the cooling or heat transfer tubes of the apparatus.More particularly, the invention deals with the use of tubes having alarge diameter or thick wall structure where mounted in the inner tubesheets and a thinner wall structure where mounted in the outer tubesheets, thereby providing a positive control and regulation of leakagesdue to corrosion, cracking or the like to avoid contamination of thecirculated air circulated around the tubes inwardly of the inner tubesheets.

The novel features of the invention will be best understood from thefollowing description, when taken together with the accompanyingdrawing, in which certain embodiments of the invention are disclosedand, in which, the separate parts are designated by suitable referencecharacters in each of the views, and in which:

Fig. 1 is a sectional view through a portion of an apparatusillustrating the mounting of one tube in a pair of tube plates at oneend portion of the apparatus; and t Fig. 2 is a sectional detail view ofone end portion of a tube, preparatory to assemblage in tube plates ofthe apparatus.

In apparatus of the type and kind under consideration used as a heatexchanger or cooler, difficulty has been experienced in providing adefinite control of the cooling fluid employed to prevent contamination.Several efforts have been made to provide solutions to this problem.

It is generally known that corrosion or breakdowns usually occur in thetubes where they are mounted in the tube plates and this corrosion orbreakdown usually starts at the free end portions of the tubes. Thepurpose of my invention is to so construct tubes in apparatus of thekind under consideration as to definitely and positively locate tubebreakdowns in the outermost tube sheet, so as to facilitate plugging orsealing of the remainder of the tube until such time as repair can bemade. Here it is well to keep in mind that apparatus of the type andkind under consideration are usually installed on ships where impure orsalt water is utilized as the cooling medium.

Apparatus of the type and kind under consideration is generally known inthe art and, for this reason, I have shown in Fig. 1 of the drawing justa portion of one end of the apparatus, it being understood that bothends of the apparatus are the same orsubstantially the same, except forthe detailsof the header construction.

In Fig. l, of the drawing, I have shown at 10 and II inner and outertube plates of the apparatus, the inner tube plate forming one wall ofan air circulating chamber l2, whereas a header i3 is mounted outwardlyof the plate H. The header in the construction shown is formed by anannular double flanged casing 14, the flange 15 of which is secured tothe plates l0 and ll; whereas an outer cover plate 16 is secured to theother flange i1.; The latter coupling is made through the medium ofbolts 18; whereas the first coupling is made by a. series of studs 19,with which nuts 20 are attached. The studs I9, are adapted to bring theplates Ill and H into firm engagement with a spacing ring 2 I, havingsuit,- able gaskets,- as indicated at 22. The ring 2! forms, betweenadjacent surfaces of the plates ill and I: i, a chamber 23. Formed inthe plate ll isan aperture 24, which opens into the chamber 23 and outthrough the peripheral edge of the plate, as indicated at 25 in dottedlines. This aperture may be used as a means for drainage and also as ameansfor testing the tube mountingsin the plates in the manners known inthe art.

At 26 I have indicated part of the housing welded or otherwise securedto the plate H! con ;trolling the transmission of air into the apparatusaround a plurality of cooling tubes, one of which is shown at 21, inFig. 1. It will be understood that the tubes extend through the chamberI2 from one header to the other and are coupled with pairs of tubeplates similar to the plates 10 and II at the other unshown end of thetube 21. The tube plates l0 and H have alined apertures 28 and 29 forthe reception of large diameter circumferentially continuous solid endportions 30 and the integral smaller diameter circumferentiallycontinuous solid weakened thin wall end portions 3| of the tubes 21,when the tubes are in their normal fabrication, as seen in Fig. 2 of thedrawing.

After arranging the end portions 30, 3| in the respective tube plates 10and 11 substantially in the position, as seen in Fig. 1, the bore 32 ofthe tube 21 is expanded adjacent the end portions 30, 31 to extend partof the materials of said end portions into sealing grooves 33, 34 formedin the walls of the apertures 28 and 29. Any desired number of thegrooves 33, 34 can be employed in each tube plate. Each tube 21 has aseries of longitudinally arranged cooling fins 35 toimprove theefiiciency of'heat exchanging, particularly when the apparatus isutilized as an air cooler, the fins facilitating a greater exposure ofthe cooling surfaces to the air circulated through the chamber 12.

In the accompanying drawing and, for purposes of illustration, thereduced or smaller outside diameter end 3| has been exaggerated to someextent in order to clearly illustrate a difference in this end, ascompared with the portion 30. Keeping in mind that corrosions andbreakdowns of the tube mountings usually occur in the tube plates. byproviding tubes having reduced diameter ends and space between tubesheets ill and H, a definite control is provided to localize tubebreakdowns between the inner tube sheet I and the end of the tube, thuskeeping failures and leakage therefrom confined to chamber 23, fromwhich it might be drained oif without contamination to the aircirculating chamber i2.

With cooling units or heat exchangers of the character underconsideration, difliculties have been experienced in having a tube leakdevelop which has resulted in contamination by reason of the leakentering the circulating chamber, through which the medium to be cooledpasses. Many efforts have been made to endeavor to obviate thisdifnculty, even to the extent of a double tube structure but, even here,the real problem has never been solved and, in this, the cost of suchinstallations has been extremely excessive. By simply providing reducedends on the several tubes and sealing these in the outer tube sheets inthe manner here defined, a reasonably definite control is provided tolocate breakdowns in the structures of the kind under consideration,thus facilitating the continuation of operation of the apparatus,particularly when on board ship, until such time as the proper repaircan be made and without shutting down the operation of the apparatus. Incases of this type and kind, it is customary to plug the leaking tube,preferably withinthe inner tube sheet, thus dispensing with the use ofthe tube and cuttingdown the efliciency of the apparatus only to thisextent.

It will be apparent that, in illustrating one use of my invention, Ihave referred for the most part to utilizing air as a cooling medium andhave referred to the cooling of motors and uses of motors on board ship.More generally speaking, however, the heat exchanger is adapted for usein connection with apparatus of any type or kind regardless of thelocation of such apparatus and the particular cooling medium employedwill be such as to suit the difierent uses.

Having fully described my invention, what I claim as new and desire tosecure by Letters Patent is:

In apparatus of the class described, employing a pair of spaced tubesheets with a chamber therebetween, one tube sheet comprising the innersheet of the apparatus and the other the outer sheet, said tube sheetshaving alined bores, the bore of the outer tube sheet being of smallerdiameter than the corresponding bore of the inner tube sheet, acirculating tube mounted in said tube sheets, said tube having acircumferentially continuous heavy solid wall arranged in the bore ofthe inner tube sheet and terminating in said chamber, an integrallyreduced end portion on said tube, said end portion comprising acircumferentially continuous thin weakened wall 5 ucture arranged in thebore of the outer tube sheet and being partially disposed in saidchamher, said tube having a substantially uniform diameter boreextending continuously through the small diameter weakened wall portion,the bores of said tube sheets having annular grooves, and both the heavyand thin walls of said tube having expanded parts arranged on outer surfaces only thereof and extending into said grooves in sealing the tubein the bores of both of said tube sheets and with respect to saidchamber.

NICHOLAS WEBER.

References Cited in the file of this patent UNITED STATES PATENTS NumberName Date 1,589,646 Hicks June 22, 1926 1,614,159 Smith Jan. 11, 19271,962,170 Blennerhassett June 12, 193% 2,152,266 McNeal Mar. 28, 19392,187,555 Flindt Jan. 16, 1940' FOREIGN PATENTS Number Country Date432,230 Great Britain July 23, 1935

